Interpretive Summary: Reports have detailed fatal and near-fatal anaphylactic reactions occurring in adolescents and adults following the ingestion of peanuts or peanut products. Currently, the only effective treatment for patients with peanut hypersensitivity is avoidance of any food products which contain the allergen. This is becoming more difficult, due to the inclusion of peanuts and peanut products as protein extenders in many different foods. One potential immunotherapeutic approach to food hypersensitivity might include the modulation of T-cell development to favor a non-allergic response by alteration of the allergen. This and other immunotherapeutic approaches require in-depth knowledge of the T-cell epitope sequence, and T-cell signaling pathways that are activated by allergen-specific interaction with receptors on the surface of immune cells. Here, we established peanut-specific T-cell lines from 23 different individuals, 17 of which are obtained from allergic, and 5 from non-allergic individuals. These T cells are then used to identify T-cell binding sites on the major peanut allergen, Ara h 2. The transmittal of the intracellular signals are then assessed towards development of immunotherapeutic tools.

Technical Abstract:
Reports have detailed fatal and near-fatal anaphylactic reactions occurring in adolescents and adults following the ingestion of peanuts or peanut products. Currently, the only effective treatment for patients with peanut hypersensitivity is avoidance of any food products which contain the allergen. This is becoming more difficult, due to the inclusion of peanuts and peanut products as protein extenders in many different foods. A potential immunotherapeutic approach to food hypersensitivity might include the modulation of Th cell development to favor Th1 cytokine responses by alteration of T-cell epitope structure. All of these approaches require in-depth knowledge of the T-cell epitope structure, and T-cell signaling pathways that are activated by allergen-specific interaction with receptors. Here, we established peanut-specific T cell lines from 23 different cell lines, 17 of which are obtained from allergic, and 5 from non-allergic individuals. We determined that the majority of them are CD4 + using FACS analysis. T cell epitope mapping of Ara h 2 identified 5 distinct T cell receptor (TCR) binding epitopes, which were used in T cell proliferation and signal transduction assays to characterize the T-cell responses to this major peanut allergen.